Please don’t use a thesaurus. It does terrible things to your writing. Yes, that’s right. Do yourself a favour and forget about thesauruses. They’re harmful unless used correctly.

Usually, thesaurus-users are looking for a different word for an idea they have in mind. The word they already know for that idea seems tired or worn out. They want a fresh word.

Or they feel that the words they’re using don’t have gravity (that is, they don’t seem important or weighty). They want their writing to sound more sophisticated or more educated.

Or they just like using a lot of different words. New words are fun.

So they go to the thesaurus, look up the word they do know, and get an exciting array of other choices that, supposedly, mean the same thing.

Problem is, no thesaurus that I know—I own more than a dozen—has definitions in the thesaurus entries. Unless you already know all the words in question, there’s no way at all to determine which word is the right word.

And believe me, most of the synonyms given in a thesaurus are not the right words.

For example, if you look up frank, meaning “honest, direct (when speaking or writing), or straightforward”, you might find candid, open, free, round, blunt, naive, and guileless. (These come from three thesauruses.)

I’ll admit that a thesaurus can be useful if there’s a word on the tip of your tongue (meaning, you can’t quite remember it). A thesaurus is good at reminding you of words that you already know. If blunt was the word you were forgetting, then now you are reminded of it.

Really, though, if you can’t think of the word, then it probably isn’t the right word in the first place.

If you don’t know the synonyms that are suggested—or better, if you don’t know all the uses of a synonym—then there’s no guidance at all as to which one to choose. So people tend to choose a word willy-nilly (without care or scruple) as if they all serve the same purpose.

This is also true of people who use bilingual dictionaries, which also tend to be rather sparse in offering good contextual information on how best to use a word.

Let’s look at the synonyms for frank. For one thing, they cannot all be simply slotted into the same hole in the same sentence. Try it:

Let me be frank with you. The original sentence. It means, “Let me tell you the truth without hiding what I’m thinking.”

Let me be honest with you. This is almost synonymous with the sentence above, although many people would tell you that if someone says “let me be honest”, then they’re probably about to tell you a lie and if they say “let me be frank”, they’re probably about to say something hurtful.

Let me be free with you. This doesn’t work at all. The only way “free” really works as a synonym of “frank” is in a sentence like “He was free with his opinions,” meaning “He gave his opinions frankly.”

Let me be blunt with you. This kind of works, but it’s better just as “Let me be blunt.”

Let me be naive with you. This doesn’t work at all. Naive is only vaguely related to uses of frank when it is used to describe someone as having a “frank visage” or “frank face”, meaning that all of their emotions and thoughts seem to be evident in their facial expressions.

Let me be guileless with you. This has the same problem as naive. Being frank is a wilful act. You do it on purpose. Being guileless is something that you are without trying and probably without realizing.

Let me be round with you. This doesn’t work, either. What, pray tell, is round doing in there? Well, it belongs to an old-fashioned meaning that is pretty close to the meaning of frank, but, unlike frank, you’d never use it to describe a person but only to describe the type of language they were using. You most often find it today in the adverb form, as in, “She cursed him roundly.” It’s also related to to round on somebody, which means to suddenly attack someone, usually with harsh, angry language.

As you can see, each of these supposed synonyms for frank comes with its own connotations. Connotations are like little flags of useful information that tell you under what circumstances a word should be used.

You can only learn the connotations if you read or talk a lot in the language in question, or if you have high-quality reference works that provide them.

So if you insist on using a thesaurus, your best bet is to make sure that you look up the synonyms you find there in a dictionary.

I should also add that if you find yourself going to the thesaurus in order to make your writing seem better than it is, then you have a larger problem than deciding which word to use.

Maybe what you’re writing about is what is really in need of changing. Maybe your topic is stale, your subject matter weak, or your inspiration lacking. Finding a different word isn’t going to fix that.

If you’re looking for a new word to represent an old idea because you’ve already used the original word too many times, then maybe you’re putting lipstick on a pig. Maybe it’s time to start over.